Fictional Fans

Is there a general term for the sort of thing represented by "Teninch" fic, where people put together random characters played by Billie Piper and David Tennant other than Rose and the Doctor? I have been browsing Hitchhiker's Guide fic for a couple of days and have run across both Sherlock and Khan in fics which I therefore assume have Martin Freeman's Arthur Dent in mind, since they have both been played by Benedict Cumberbatch.

(not sure what other tags might apply)